Humans need food, shelter and water to survive. Our planet provides the resources to help us fulfill these needs. But exactly how much of an impact are we making on our planet? Will we reach a point where the Earth can no longer support our growing population?

Just like a bank account tracks money spent and earned, the human footprint measures the balance between the resources that people use and what the Earth has in its supply. A human footprint can be calculated for an individual, town or country, and is used to show the intensity of human pressures on the environment. The Human Footprint map layer does this by deriving a value representing the magnitude of the human footprint per one square kilometer (0.39 square miles) for every biome.

This map layer was created by scientists with the Wildlife Conservation Society and Columbia University’s Human Footprint project to highlight where human pressures are most extreme in hopes of reducing environmental damage. The Human Footprint map asks an important question: Where are the world’s least disturbed wilderness areas?

The Human Footprint map was produced by combining nine global data layers that spatially visualize what is presumed to be the most prominent ways we influence the environment. These layers include human population pressure (population density), human land use and infrastructure (built-up areas, nighttime lights, land use/land cover) and human access (coastlines, roads, railroads, navigable rivers). Based on the amount of overlap between layers, each square kilometer value is scaled between one and 100 for each biome. For example, if an area in a Moist Tropical Forest biome scored a value of one, that square kilometer of land is part of the 1% least influenced/most wild area in its biome. Knowing this, we can target areas with more wilderness in every biome for preservation and identify areas with high human footprints for mitigation.

Though the Human Footprint map contains helpful data, there are limitations that must be considered. The map doesn’t show change over time, which can impede accurate interpretation. For example, rapid urbanization increases an area’s human footprint, but urbanization is happening so quickly in many countries that maps quickly become outdated and inaccurate.

Misconceptions also may occur when comparing an area with rapid urbanization to one with slower urbanization. Two different parts of the world can have the same human footprint but very different histories. As just one example, the United States historically has been the world’s biggest polluter. Looking at the map, one might assume that a country that is mostly red, such as India, pollutes just as much, if not more than the United States. However, the data on the map mostly represents India’s rapid—and recent—industrialization. People might make false comparisons, like assuming that people who live in areas with similar footprints have similar lifestyles. But living conditions in rapidly urbanizing areas are significantly different from areas that grew more slowly. Areas with rapid urbanization often have poor infrastructure, which can lead to many issues, such as greater pollution and health problems for residents. This is important to keep in mind when comparing different areas of the map.

Human footprint maps also don’t show relationships between places with higher human footprints and places with lower footprints. People who live in places with the smallest human footprint, like deserts or low-lying islands, may face the most danger from climate change, while those in the places with bigger footprints are at less risk. In addition, innovation around sustainable development in areas with bigger footprints might help areas with smaller footprints.

It's important to recognize that the concept of the human footprint has the possibility to shift the focus away from government and corporate accountability and onto individual responsibility. In fact, companies in the oil industry developed the notion of a personal carbon footprint to divert attention from the environmental harm the companies were causing and redirect individuals’ focus to their personal choices instead. But many contributions to the human footprint require systemic change. For example, food production and use are huge contributors to the human footprint. Governments and industry leaders in countries with high food production must invest in technologies that allow people to produce the same amount of food on less land. Governments in countries that are food-rich also need to focus on policies that decrease food waste.

Despite these issues, the Human Footprint map is a good start for understanding humanity’s impact on the natural world. It helps people see the big picture and understand how human actions affect different regions of the planet. It also encourages smarter choices about how we use resources. When used in conjunction with other data, the Human Footprint map can inform efforts to protect and restore the environment.

So how can you reduce the human footprint? Here are just a few ways:

• Advocate: Vote for politicians and policies that aim to lower the human footprint and encourage others to do the same. Donate to or volunteer for organizations that are working to curb climate change.
• Research: Learn more about the industries that contribute the most to climate change and share that information with others.
• Recycle: Recycling helps conserve resources, reduces water and air pollution and helps save space in overcrowded landfills.
• Use less water: Reduce your water consumption by taking shorter showers and turning off the water when brushing your teeth.

Reduce driving: When you can, walk, bike or take the bus instead of driving. If you must drive, try to carpool with other people to reduce pollution.